Q.Assertion: In mono haloarenes, electrophilic substitution occurs at ortho and para positions. Reason: Halogen atom is a ring deactivator.

Step 1. Assertion: in monohaloarenes, electrophilic substitution occurs at ortho and para positions -- true, since the halogen's lone-pair resonance donation raises electron density specifically at those positions.

Step 2. Reason: the halogen atom is a ring deactivator -- also true, since the halogen's -I inductive effect withdraws electron density overall, making the ring less reactive than plain benzene.

Step 3. However, deactivation (the reason given) is NOT what causes ortho/para direction (the assertion). Deactivation is caused by the inductive (-I) effect; ortho/para direction is caused by the SEPARATE resonance (+M) effect of the halogen's lone pair. A substituent can in principle be a deactivator and still be a meta director (like -NO2) -- it just happens that halogen's resonance donation specifically favour …

Verify the assertion and reason are each true on their own, then check specifically whether deactivation (an inductive effect) is what CAUSES ortho/para direc …

• Picking (i), assuming that because both statements sound related and both are true, the reason must explain the assertion -- but ortho/para direction is a resonance phenomenon, while ring deactivation is …